1. Field
Embodiments of the invention relate to electronic systems and, in particular, to radio frequency (RF) directional couplers.
2. Description of the Related Art
RF power amplifiers can be used to boost the power of a RF signal having a relatively low power. Thereafter, the boosted RF signal can be used for a variety of purposes, included driving the antenna of a transmitter.
A power amplifier can be included in a mobile phone to amplify a RF signal for transmission. For example, in a mobile phone having a time division multiple access (TDMA) architecture, such as those found in Global System for Mobile Communications (GSM), code division multiple access (CDMA), and wideband code division multiple access (W-CDMA) systems, a power amplifier can be used to shift power envelopes up and down within prescribed limits of power versus time. It can be important manage the amplification of a RF signal, as a particular mobile phone can be assigned a transmission time slot for a particular frequency channel. A power amplifier can be employed to aid in regulating the power level of the RF signal over time, so as to prevent signal interference from transmission during an assigned receive time slot and to reduce power consumption.
One or more directional couplers can be used in a system employing a power amplifier. For example, a directional coupler can monitor and measure the power of a power amplifier output signal to aid in controlling the power amplifier.
There is a need for improved for improved directional couplers in power amplifier systems.